gdb/i386bsd-nat.c

   1 /* Native-dependent code for modern i386 BSD's.
   2    Copyright 2000, 2001, 2002 Free Software Foundation, Inc.
   3
   4    This file is part of GDB.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #include "defs.h"
  22 #include "inferior.h"
  23 #include "regcache.h"
  24
  25 #include "gdb_assert.h"
  26 #include <signal.h>
  27 #include <stddef.h>
  28 #include <sys/types.h>
  29 #include <sys/ptrace.h>
  30 #include <machine/reg.h>
  31 #include <machine/frame.h>
  32
  33 #ifdef HAVE_SYS_PROCFS_H
  34 #include <sys/procfs.h>
  35 #endif
  36
  37 #ifndef HAVE_GREGSET_T
  38 typedef struct reg gregset_t;
  39 #endif
  40
  41 #ifndef HAVE_FPREGSET_T
  42 typedef struct fpreg fpregset_t;
  43 #endif
  44
  45 #include "gregset.h"
  46 #include "i386-tdep.h"
  47 \f
  48
  49 /* In older BSD versions we cannot get at some of the segment
  50    registers.  FreeBSD for example didn't support the %fs and %gs
  51    registers until the 3.0 release.  We have autoconf checks for their
  52    presence, and deal gracefully with their absence.  */
  53
  54 /* Registers we shouldn't try to fetch.  */
  55 #if !defined (CANNOT_FETCH_REGISTER)
  56 #define CANNOT_FETCH_REGISTER(regno) cannot_fetch_register (regno)
  57 #endif
  58
  59 /* Registers we shouldn't try to store.  */
  60 #if !defined (CANNOT_STORE_REGISTER)
  61 #define CANNOT_STORE_REGISTER(regno) cannot_fetch_register (regno)
  62 #endif
  63
  64 /* Offset to the gregset_t location where REG is stored.  */
  65 #define REG_OFFSET(reg) offsetof (gregset_t, reg)
  66
  67 /* At reg_offset[REGNO] you'll find the offset to the gregset_t
  68    location where the GDB register REGNO is stored.  Unsupported
  69    registers are marked with `-1'.  */
  70 static int reg_offset[] =
  71 {
  72   REG_OFFSET (r_eax),
  73   REG_OFFSET (r_ecx),
  74   REG_OFFSET (r_edx),
  75   REG_OFFSET (r_ebx),
  76   REG_OFFSET (r_esp),
  77   REG_OFFSET (r_ebp),
  78   REG_OFFSET (r_esi),
  79   REG_OFFSET (r_edi),
  80   REG_OFFSET (r_eip),
  81   REG_OFFSET (r_eflags),
  82   REG_OFFSET (r_cs),
  83   REG_OFFSET (r_ss),
  84   REG_OFFSET (r_ds),
  85   REG_OFFSET (r_es),
  86 #ifdef HAVE_STRUCT_REG_R_FS
  87   REG_OFFSET (r_fs),
  88 #else
  89   -1,
  90 #endif
  91 #ifdef HAVE_STRUCT_REG_R_GS
  92   REG_OFFSET (r_gs)
  93 #else
  94   -1
  95 #endif
  96 };
  97
  98 #define REG_ADDR(regset, regno) ((char *) (regset) + reg_offset[regno])
  99
 100 /* Macro to determine if a register is fetched with PT_GETREGS.  */
 101 #define GETREGS_SUPPLIES(regno) \
 102   ((0 <= (regno) && (regno) <= 15))
 103
 104 #ifdef HAVE_PT_GETXMMREGS
 105 /* Set to 1 if the kernel supports PT_GETXMMREGS.  Initialized to -1
 106    so that we try PT_GETXMMREGS the first time around.  */
 107 static int have_ptrace_xmmregs = -1;
 108 #endif
 109
 110 /* Return nonzero if we shouldn't try to fetch register REGNO.  */
 111
 112 static int
 113 cannot_fetch_register (int regno)
 114 {
 115   return (reg_offset[regno] == -1);
 116 }
 117 \f
 118
 119 /* Transfering the registers between GDB, inferiors and core files.  */
 120
 121 /* Fill GDB's register array with the general-purpose register values
 122    in *GREGSETP.  */
 123
 124 void
 125 supply_gregset (gregset_t *gregsetp)
 126 {
 127   int i;
 128
 129   for (i = 0; i < I386_NUM_GREGS; i++)
 130     {
 131       if (CANNOT_FETCH_REGISTER (i))
 132         supply_register (i, NULL);
 133       else
 134         supply_register (i, REG_ADDR (gregsetp, i));
 135     }
 136 }
 137
 138 /* Fill register REGNO (if it is a general-purpose register) in
 139    *GREGSETPS with the value in GDB's register array.  If REGNO is -1,
 140    do this for all registers.  */
 141
 142 void
 143 fill_gregset (gregset_t *gregsetp, int regno)
 144 {
 145   int i;
 146
 147   for (i = 0; i < I386_NUM_GREGS; i++)
 148     if ((regno == -1 || regno == i) && ! CANNOT_STORE_REGISTER (i))
 149       regcache_collect (i, REG_ADDR (gregsetp, i));
 150 }
 151
 152 #include "i387-tdep.h"
 153
 154 /* Fill GDB's register array with the floating-point register values
 155    in *FPREGSETP.  */
 156
 157 void
 158 supply_fpregset (fpregset_t *fpregsetp)
 159 {
 160   i387_supply_fsave ((char *) fpregsetp);
 161 }
 162
 163 /* Fill register REGNO (if it is a floating-point register) in
 164    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 165    do this for all registers.  */
 166
 167 void
 168 fill_fpregset (fpregset_t *fpregsetp, int regno)
 169 {
 170   i387_fill_fsave ((char *) fpregsetp, regno);
 171 }
 172
 173 /* Fetch register REGNO from the inferior.  If REGNO is -1, do this
 174    for all registers (including the floating point registers).  */
 175
 176 void
 177 fetch_inferior_registers (int regno)
 178 {
 179
 180   if (regno == -1 || GETREGS_SUPPLIES (regno))
 181     {
 182       gregset_t gregs;
 183
 184       if (ptrace (PT_GETREGS, PIDGET (inferior_ptid),
 185                   (PTRACE_ARG3_TYPE) &gregs, 0) == -1)
 186         perror_with_name ("Couldn't get registers");
 187
 188       supply_gregset (&gregs);
 189       if (regno != -1)
 190         return;
 191     }
 192
 193   if (regno == -1 || regno >= FP0_REGNUM)
 194     {
 195       fpregset_t fpregs;
 196 #ifdef HAVE_PT_GETXMMREGS
 197       char xmmregs[512];
 198
 199       if (have_ptrace_xmmregs != 0 &&
 200           ptrace(PT_GETXMMREGS, PIDGET (inferior_ptid),
 201                  (PTRACE_ARG3_TYPE) xmmregs, 0) == 0)
 202         {
 203           have_ptrace_xmmregs = 1;
 204           i387_supply_fxsave (xmmregs);
 205         }
 206       else
 207         {
 208           if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
 209                       (PTRACE_ARG3_TYPE) &fpregs, 0) == -1)
 210             perror_with_name ("Couldn't get floating point status");
 211
 212           supply_fpregset (&fpregs);
 213         }
 214 #else
 215       if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
 216                   (PTRACE_ARG3_TYPE) &fpregs, 0) == -1)
 217         perror_with_name ("Couldn't get floating point status");
 218
 219       supply_fpregset (&fpregs);
 220 #endif
 221     }
 222 }
 223
 224 /* Store register REGNO back into the inferior.  If REGNO is -1, do
 225    this for all registers (including the floating point registers).  */
 226
 227 void
 228 store_inferior_registers (int regno)
 229 {
 230
 231   if (regno == -1 || GETREGS_SUPPLIES (regno))
 232     {
 233       gregset_t gregs;
 234
 235       if (ptrace (PT_GETREGS, PIDGET (inferior_ptid),
 236                   (PTRACE_ARG3_TYPE) &gregs, 0) == -1)
 237         perror_with_name ("Couldn't get registers");
 238
 239       fill_gregset (&gregs, regno);
 240
 241       if (ptrace (PT_SETREGS, PIDGET (inferior_ptid),
 242                   (PTRACE_ARG3_TYPE) &gregs, 0) == -1)
 243         perror_with_name ("Couldn't write registers");
 244
 245       if (regno != -1)
 246         return;
 247     }
 248
 249   if (regno == -1 || regno >= FP0_REGNUM)
 250     {
 251       fpregset_t fpregs;
 252 #ifdef HAVE_PT_GETXMMREGS
 253       char xmmregs[512];
 254
 255       if (have_ptrace_xmmregs != 0 &&
 256           ptrace(PT_GETXMMREGS, PIDGET (inferior_ptid),
 257                  (PTRACE_ARG3_TYPE) xmmregs, 0) == 0)
 258         {
 259           have_ptrace_xmmregs = 1;
 260
 261           i387_fill_fxsave (xmmregs, regno);
 262
 263           if (ptrace (PT_SETXMMREGS, PIDGET (inferior_ptid),
 264                       (PTRACE_ARG3_TYPE) xmmregs, 0) == -1)
 265             perror_with_name ("Couldn't write XMM registers");
 266         }
 267       else
 268         {
 269           have_ptrace_xmmregs = 0;
 270 #endif
 271           if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
 272                       (PTRACE_ARG3_TYPE) &fpregs, 0) == -1)
 273             perror_with_name ("Couldn't get floating point status");
 274
 275           fill_fpregset (&fpregs, regno);
 276
 277           if (ptrace (PT_SETFPREGS, PIDGET (inferior_ptid),
 278                       (PTRACE_ARG3_TYPE) &fpregs, 0) == -1)
 279             perror_with_name ("Couldn't write floating point status");
 280 #ifdef HAVE_PT_GETXMMREGS
 281         }
 282 #endif
 283     }
 284 }
 285 \f
 286
 287 /* Support for debug registers.  */
 288
 289 #ifdef HAVE_PT_GETDBREGS
 290
 291 /* Not all versions of FreeBSD/i386 that support the debug registers
 292    have this macro.  */
 293 #ifndef DBREG_DRX
 294 #define DBREG_DRX(d, x) ((&d->dr0)[x])
 295 #endif
 296
 297 static void
 298 i386bsd_dr_set (int regnum, unsigned int value)
 299 {
 300   struct dbreg dbregs;
 301
 302   if (ptrace (PT_GETDBREGS, PIDGET (inferior_ptid),
 303               (PTRACE_ARG3_TYPE) &dbregs, 0) == -1)
 304     perror_with_name ("Couldn't get debug registers");
 305
 306   /* For some mysterious reason, some of the reserved bits in the
 307      debug control register get set.  Mask these off, otherwise the
 308      ptrace call below will fail.  */
 309   DBREG_DRX ((&dbregs), 7) &= ~(0x0000fc00);
 310
 311   DBREG_DRX ((&dbregs), regnum) = value;
 312
 313   if (ptrace (PT_SETDBREGS, PIDGET (inferior_ptid),
 314               (PTRACE_ARG3_TYPE) &dbregs, 0) == -1)
 315     perror_with_name ("Couldn't write debug registers");
 316 }
 317
 318 void
 319 i386bsd_dr_set_control (unsigned long control)
 320 {
 321   i386bsd_dr_set (7, control);
 322 }
 323
 324 void
 325 i386bsd_dr_set_addr (int regnum, CORE_ADDR addr)
 326 {
 327   gdb_assert (regnum >= 0 && regnum <= 4);
 328
 329   i386bsd_dr_set (regnum, addr);
 330 }
 331
 332 void
 333 i386bsd_dr_reset_addr (int regnum)
 334 {
 335   gdb_assert (regnum >= 0 && regnum <= 4);
 336
 337   i386bsd_dr_set (regnum, 0);
 338 }
 339
 340 unsigned long
 341 i386bsd_dr_get_status (void)
 342 {
 343   struct dbreg dbregs;
 344
 345   /* FIXME: kettenis/2001-03-31: Calling perror_with_name if the
 346      ptrace call fails breaks debugging remote targets.  The correct
 347      way to fix this is to add the hardware breakpoint and watchpoint
 348      stuff to the target vector.  For now, just return zero if the
 349      ptrace call fails.  */
 350   if (ptrace (PT_GETDBREGS, PIDGET (inferior_ptid),
 351               (PTRACE_ARG3_TYPE) & dbregs, 0) == -1)
 352 #if 0
 353     perror_with_name ("Couldn't read debug registers");
 354 #else
 355     return 0;
 356 #endif
 357
 358   return DBREG_DRX ((&dbregs), 6);
 359 }
 360
 361 #endif /* PT_GETDBREGS */
 362 \f
 363
 364 /* Support for the user struct.  */
 365
 366 /* Return the address register REGNO.  BLOCKEND is the value of
 367    u.u_ar0, which should point to the registers.  */
 368
 369 CORE_ADDR
 370 register_u_addr (CORE_ADDR blockend, int regno)
 371 {
 372   return (CORE_ADDR) REG_ADDR (blockend, regno);
 373 }
 374
 375 #include <sys/param.h>
 376 #include <sys/user.h>
 377
 378 /* Return the size of the user struct.  */
 379
 380 int
 381 kernel_u_size (void)
 382 {
 383   return (sizeof (struct user));
 384 }
 385 \f
 386 void
 387 _initialize_i386bsd_nat (void)
 388 {
 389   int offset;
 390
 391   /* To support the recognition of signal handlers, i386bsd-tdep.c
 392      hardcodes some constants.  Inclusion of this file means that we
 393      are compiling a native debugger, which means that we can use the
 394      system header files and sysctl(3) to get at the relevant
 395      information.  */
 396
 397 #if defined (__FreeBSD_version) && __FreeBSD_version >= 400011
 398   extern int i386fbsd4_sc_reg_offset[];
 399 #define SC_REG_OFFSET i386fbsd4_sc_reg_offset
 400 #elif defined (__FreeBSD_version) && __FreeBSD_version >= 300005
 401   extern int i386fbsd_sc_reg_offset[];
 402 #define SC_REG_OFFSET i386fbsd_sc_reg_offset
 403 #elif defined (NetBSD) || defined (__NetBSD_Version__)
 404   extern int i386nbsd_sc_reg_offset[];
 405 #define SC_REG_OFFSET i386nbsd_sc_reg_offset
 406 #elif defined (OpenBSD)
 407   extern int i386obsd_sc_reg_offset[];
 408 #define SC_REG_OFFSET i386obsd_sc_reg_offset
 409 #else
 410   extern int i386bsd_sc_reg_offset[];
 411 #define SC_PC_OFFSET i386bsd_sc_reg_offset
 412 #endif
 413
 414   /* We only check the program counter, stack pointer and frame
 415      pointer since these members of `struct sigcontext' are essential
 416      for providing backtraces.  More checks could be added, but would
 417      involve adding configure checks for the appropriate structure
 418      members, since older BSD's don't provide all of them.  */
 419
 420 #define SC_PC_OFFSET SC_REG_OFFSET[I386_EIP_REGNUM]
 421 #define SC_SP_OFFSET SC_REG_OFFSET[I386_ESP_REGNUM]
 422 #define SC_FP_OFFSET SC_REG_OFFSET[I386_EBP_REGNUM]
 423
 424   /* Override the default value for the offset of the program counter
 425      in the sigcontext structure.  */
 426   offset = offsetof (struct sigcontext, sc_pc);
 427
 428   if (SC_PC_OFFSET != offset)
 429     {
 430       warning ("\
 431 offsetof (struct sigcontext, sc_pc) yields %d instead of %d.\n\
 432 Please report this to <bug-gdb@gnu.org>.",
 433                offset, SC_PC_OFFSET);
 434     }
 435
 436   SC_PC_OFFSET = offset;
 437
 438   /* Likewise for the stack pointer.  */
 439   offset = offsetof (struct sigcontext, sc_sp);
 440
 441   if (SC_SP_OFFSET != offset)
 442     {
 443       warning ("\
 444 offsetof (struct sigcontext, sc_sp) yields %d instead of %d.\n\
 445 Please report this to <bug-gdb@gnu.org>.",
 446                offset, SC_SP_OFFSET);
 447     }
 448
 449   SC_SP_OFFSET = offset;
 450
 451   /* And the frame pointer.  */
 452   offset = offsetof (struct sigcontext, sc_fp);
 453
 454   if (SC_FP_OFFSET != offset)
 455     {
 456       warning ("\
 457 offsetof (struct sigcontext, sc_fp) yields %d instead of %d.\n\
 458 Please report this to <bug-gdb@gnu.org>.",
 459                offset, SC_FP_OFFSET);
 460     }
 461
 462   SC_FP_OFFSET = offset;
 463 }